Did someone shorten the straightaway between Turn 11 and the start-finish line here at Laguna Seca? The track also seems strangely narrower since our last visit, and the kink that is Turn 1 seems more like, well, an actual turn as we hurtle toward it in this gleaming silver 2011 Mercedes-Benz SLS AMG. That's what a 563-horsepower 6.2-liter AMG V8 engine can do to perception when it's set deep within the all-aluminum chassis of a purpose-built ultra-performance sports car such as this. But blunt-force V8 engines with a calm in-town demeanor and an intoxicating exhaust note are hardly news where AMG is concerned — the company from Affalterbach has been impressing us with its approach to V8 high performance for some time. No, the news here is the car itself. The 2011 Mercedes-Benz SLS AMG is AMG's first complete car, designed and developed entirely in-house with no donor Benz chassis to start from. That the SLS AMG is destined to be a flagship car for Mercedes-Benz (as well as the re-embodiment of the beloved 300SL Gullwing) is a testament to the engineering resources of what once was just a small, independent tuning company and now is the official high-performance division of Mercedes-Benz.Not a Warmed-Over SLR McLaren
Comparisons to the SLR McLaren are unavoidable, as both it and the SLS AMG are front-midengine coupes with impossibly long hoods and oddly hinged doors. The SLR paradoxically paired an extremely expensive carbon-fiber chassis with a traditional five-speed automatic transmission, whereas the SLS employs a less costly (but still exotic) aluminum unibody and a rear-mounted seven-speed automated manual transaxle. But AMG wasn't yet ready to deliver on the entire automotive package back when the SLR was conceived, so its involvement with that project was more or less limited to providing the supercharged 5.5-liter V8 engine. So AMG got to work by steadily expanding its contribution to mass-produced Mercedes-Benz road cars while the McLaren F1 boys were busy playing with their beloved carbon-fiber. AMG's effort eventually led to thoughtful and effective upgrades to the front suspension and brakes of the 2008 C63 AMG, a car that showed how far AMG can take a production car with a bolt-on tuning approach. From there AMG stretched a bit further to make the 2009 SL65 AMG Black Series, in which it extensively modified the body structure of an SL roadster, turning it into a rigid platform for a much more manic coupe. All of this was part of a build-up of staff and experience that would allow AMG to finally design an entire car.
Body and Soul
In deference to the 300SL, which won the 1952 24 Hours of Le Mans and was built as a production car from 1955-'63, the aluminum body shell of the SLS was designed with gullwing doors from the start. And since gullwing doors disallow the use of fixed roof rails above the side windows, the remaining slender central roof section cannot be relied on to provide much body rigidity. Instead the side sills of the SLS utilize a massive rectangular cross-section to provide the necessary chassis rigidity.
A bare SLS aluminum body shell weighs just 532 pounds, and the finished car tips the scales at just 3,573 pounds — some 277 pounds less than the carbon-fiber SLR McLaren, a car which is longer by only 0.7 inch. What's more, at 76.3 inches the SLS is actually 1.2 inches wider than an SLR. Physical comparisons to the SL63 AMG roadster are more impressive. The SLS AMG is 4.1 inches longer, 4.8 inches wider...and more than 700 pounds lighter than the roadster we drove on the Nürburgring last year. With 45 hp more, no wonder the SLS AMG will turn a lap of the Nürburgring Nordschleife in 7:40 compared to the SL63 AMG's 8:15.
Revised 6.2-liter V8
Though the SLR used a supercharged 5.5-liter AMG V8, the normally aspirated 6.2-liter V8 in the SLS shares one vital modification. That is, the wet-sump oil pan has been replaced with a dry-sump scavenging system and a remote oil tank. This allows the engine to sit far lower and farther back in the chassis. The SLS iteration of what AMG continues to call a 6.3-liter V8 (despite its actual 6,208cc displacement, an homage to the 6.3-liter Mercedes with which AMG earned its reputation in racing) has been pumped up to 563 hp through revisions to the valvetrain and the intake and exhaust systems.
We can't even see much of the most visible change, which is a new magnesium intake manifold with eight interlaced, individually tuned velocity stacks, each 11.4 inches in length and 2 inches across. Bucket-type tappets allow a more aggressive cam profile, and large-diameter tubular exhaust headers guide the spent gases out through tuned-length runners that minimize back-pressure. On the track, it adds up to a healthy shove as we exit Turn 11 at Laguna, hard on the gas and flicking through the gears in rapid succession.
All-New TransaxleThose gears actually reside between the rear wheels in a new seven-speed transaxle developed in-house specifically for the SLS. It's an automated manual with dual wet clutches, one each for the odd- and even-numbered gears. A multiple limited-slip differential resides in the same housing, slightly forward of the gear clusters. A rigid aluminum torque tube connects the transaxle to the engine. This reduces overall driveline slack immensely, as the engine and rear end aren't free to twist and buck in their mounts relative to one another. Hidden inside the torque tube is a lightweight carbon-fiber driveshaft that rotates at engine speed. Shift paddles on the steering wheel control it all in Manual mode, though the familiar console-mounted lever and a rotary dial with three additional automatic modes (Controlled Efficiency, Sport and Sport Plus) make it easy to control at whatever pace you require. On the track, we find that Sport Plus nicely initiates rapid up- and downshifts in accordance with whichever pedal we're standing on at the moment. Manual-mode shifting is aided by a set of F1-style shift indicator lights. But they seem a bit too far away from the driver's line of sight on the track and we find ourselves in the rev limiter more than once. AMG engineers are also quick to point out that final programming for the transmission is yet to be finalized in these last months before production. Of course a rear-mounted transaxle provides another obvious benefit in that it shifts weight distribution rearward. And so the front-midengine layout (the engine is behind the line of the front axle) of the SLS AMG places just 47 percent of its weight on the front tires, with the remaining 53 percent out back to put the power to the pavement.
Balance
All of this leads to a chassis that feels reassuringly responsive, rigid and well balanced. The SLS AMG responds precisely to steering inputs and we have no trouble placing the car just where we want on the track. Understeer and oversteer seem well tamed and by the 19-inch front and 20-inch rear Continental tires. There's only one thing that can upset this rapidly moving apple cart, and that's an overly enthusiastic right foot. It's quite easy to forget about the 563 hp on tap and the lightweight chassis when everything is rushing past so effortlessly. It's a bit easy to get into the throttle too hard and break the rear tires loose and get into oversteer, even with the stability control in the intermediate Sport mode. None of this is a concern on the road, where you're likely to be further from the limit with the stability control system at full watchfulness. Here the ride of the standard suspension, which uses nonadjustable monotube dampers, feels reassuringly firm and well damped. The optional AMG performance suspension features springs that are some 15 percent firmer, and the dampers have been retuned to suit, but the tires and stabilizer bars remain unchanged. As we've said of the C63 and E63, don't rush toward this option if your municipality doesn't fully fund its road maintenance crew.
Life With GullwingsThere's something about gullwing doors that makes you want to open and close them, or maybe just leave them open and stand back a few paces. These certainly provide much better access than any Lambo-style scissor doors we've ever tested, and they're easier to live with in narrow parking stalls than the funky guillotine-style doors found on the Ford GT. From the driver seat it's an easy reach for this tall test driver to the grab handle, and shorter drivers can grab hold before they're fully seated and pull it down as they slide in or use the hanging loop that AMG can provide. Unless you're an NBA star, there's no need to duck as you close these doors, either. The inner panels are scalloped to provide clearance. But there can be no map pockets, so interior storage is at a premium. The stubby rear deck lid conceals just 6.2 cubic feet of storage, just enough for weekend luggage for two. Legroom isn't terribly generous, either. Our 6-foot-2-inch frame could have used another inch of seat travel for true long-distance comfort. The rest of the car is finished in familiar Mercedes AMG fashion. The level of trim is outstanding, as is the Bang and Olufsen sound system.
An Impressive Achievement
All in all, the 2011 Mercedes-Benz SLS AMG represents an impressive achievement. It's a car that delivers just what you'd expect from a reborn gullwing Mercedes developed by the modern-day AMG.
We won't have long to wait to see production examples, either, as the 2011 SLS AMG will hit these shores late in April 2010. Orders are being taken now, but the U.S. price is still to be determined. European prices start at €177,310, but this includes a 19 percent value-added tax. We're estimating a price in the neighborhood of $235,000, notwithstanding the gas-guzzler tax we'll doubtless pay here.
Whatever the price turns out to be, it's about $200,000 less than the McLaren-built carbon-fiber SLR. And from where we sit, the SLS AMG is the far better car. Which leaves us with just one question for the guys at AMG: Where do you go from here?
